WO2011000552A2

WO2011000552A2 - Burner for combusting solid fuel

Info

Publication number: WO2011000552A2
Application number: PCT/EP2010/003947
Authority: WO
Inventors: Werner Boos
Original assignee: Holthof, Bettina
Priority date: 2009-07-02
Filing date: 2010-07-02
Publication date: 2011-01-06
Also published as: WO2011000552A3; DE102009033006A1

Abstract

The invention relates to a burner for combusting solid fuel (2), in particular biomass, comprising a burner tube (3), a burner point, a feed device (4) for conducting the fuel (2) to the burner point (4), and a primary air feed device (6). Greater performance can be achieved using the burner according to the invention, because the burner tube (3) is arranged substantially horizontally in the basic state and is composed of ceramic, because the feed device (4) protrudes into the burner device (3) on the side (8) opposite the open side (7) of the burner tube (3), and because a drive device (9) is provided to rotate the burner tube (3) about the longitudinal axis thereof so that the burner tube (3) can be rotated in such a way that the fuel (2) conducted to the burner point by the feed device (4) is both circulated and moved in the direction of the open side (7) of the burner tube (3) by means of the rotation of the burner tube (3).

Description

Burner for burning solid fuel

The invention relates to a burner for the combustion of solid fuel, in particular biomass, with a combustion tube, with a burner, with a supply device for conveying the fuel to the burner and with a primary air supply. In addition, the invention also relates to a heating system with a burner for the combustion of solid fuel. In order to generate heat energy, combustible substances are regularly burned in order to utilize the thermal energy obtained for heating media. The heating takes place with the aid of a heat exchanger, for example an air-water heat exchanger, in which the water is heated by the hot air produced during combustion of the fuels. In addition to classic burners or boilers in which fossil fuels such as petroleum, natural gas or coal are burned, there are also burners or boilers in which renewable raw materials, especially wood in the form of wood chips and pellets, are used as fuels. Such pellet boilers, which are also referred to as log wood boilers, are now available in a very large power range of about 5 to 100 kW.

In the context of this invention, the term "biomass" is to be understood as meaning renewable raw materials. In addition to wood, especially in the form of wood shavings, wood chips or wood pellets, and cereals also cereal-like substances such as rapeseed or straw, these then preferably in the form of rapeseed cake or straw pellets, and energy crops such as Miscanthus. The term "biomass" thus includes substances of organic origin, d. H. carbonaceous matter.

A number of problems have arisen in the operation of the wood pellet boilers with cereals, so far it has been difficult to achieve operation of the same quality as the intended fuel. The main problems lie in a poorer efficiency due to a worse burnout of the grain, a Increased emissions of dust, carbon monoxide, hydrocarbons and nitrogen oxides, which often exceed the permissible limits of the boilers, and an increased ash content, which leads to problems with the ash discharge and problems due to slagging.

A heating boiler with which different renewable raw materials, in particular wood pellets, cereals, rapeseed cake (in pelleted form) or straw pellets can be burned, is known from EP 1 288 570 A2. In the known boiler, in addition to the actual combustion point - the first combustion stage - a Ausbrand- or Ausglühraum provided as a second combustion stage, in which in the first combustion stage only partially burned out fuels, which still have a carbon content and thus also an energy value on can burn out. Since the Ausbrand- or Ausglühraum is arranged below the combustion chamber designed as a burner, the fuel can simply pass from the first combustion stage to the second combustion stage, that the fuel from the fuel plate falls into the Ausbrand- or Ausglühraum.

By encapsulating the first and the second combustion stage within the common combustion chamber, it is achieved that the flue gases which form during combustion or annealing of the fuels in the combustion or annealing space have lower exhaust gas values due to the somewhat lower temperatures prevailing there Combustion of the fuel in the first combustion stage resulting smoke or fuel gases are supplied and burn out together with these within the flame tube in the prevailing large heat, so that the exhaust gas values of the boiler are hardly negatively affected by the "bad" emissions from the second combustion stage , In the known boiler thus not only the efficiency is increased by the fact that the energy value of the fuels is almost completely utilized, but it is additionally made the actual associated "worse" flue gases largely harmless, that these flue gases through the extremely hot first Be passed combustion stage and continue to burn out there. A further development of this boiler is described in DE 10 2007 054 Al. In this boiler, the emission levels can be further improved, in particular the proportion of nitrogen oxides can be further reduced, that the primary air supply device is designed and arranged so that on the one hand air can be blown into the first combustion zone, on the other hand, during the burning or annealing of Fuels in Ausbrandbzw. Ausglühraum resulting flue gases are passed substantially past the primary air supply means and at the combustion point, so that the flue gases of the second combustion stage does not adversely affect the combustion of the fuel on the burner.

With these boilers, although the use of different biomass fuel, especially cereals, rapeseed cake or straw pellets, the required emission levels are met, the power range of these boilers is limited to about 50 kW, so that the use of the boiler primarily on private or agricultural area is limited.

The present invention is therefore based on the Aufgrabe to provide a burner for the combustion of solid fuels, in particular of biomass, and a heating system with a burner and at least one boiler for generating heat energy by combustion of biomass available, with the greater benefits can be reached, so that the burner or the heating system can also be used for larger facilities, such as local heating networks or public swimming pools.

This object is achieved in the burner described above in that the combustion tube is arranged substantially horizontally in the ground state and consists of ceramic, wherein the feed device protrudes on the open side of the combustion tube or the burner opposite side into the combustion tube, and that a Drive device is provided for rotating movement of the combustion tube about its longitudinal axis. By means of the drive device, the horizontally arranged combustion tube is rotatable such that the fuel conveyed by the feed device into the combustion tube is both circulated by the rotation of the combustion tube and is moved in the direction of the open side of the combustion tube.

In contrast to the boiler known from DE 10 2007 054 114 A1, for example, whose boiler wall is arranged vertically and in which the combustion point is formed by a stationary burning plate arranged inside the actual combustion chamber, the burner according to the invention serves essentially horizontally arranged, rotating combustion tube as a focal point. By a corresponding dimensioning of the combustion tube, a correspondingly large combustion chamber is formed, whereby the power can be increased.

Since the combustion tube is rotated by the drive device about its longitudinal axis, the fuel is both circulated by the rotation of the combustion tube and also moved in the direction of the open side of the combustion tube. The circulation of the fuel thereby promotes its gasification, which leads to an increase in the efficiency. In addition, it is possible to dispense with mechanical components in the region of the burning point for stirring as well as for discharging the fuel, since both movements of the fuel are effected automatically by the rotation of the combustion tube. Since arranged in the region of the burner mechanical components, such as moving elements or push grates are very susceptible to wear due to the high temperatures prevailing there, the wear of the burner according to the invention, in which can be dispensed with such mechanical components, substantially lent.

The reduction of wear is also the formation of the burner tube made of ceramic, since ceramic is on the one hand very resistant to heat, on the other hand has the property to clean itself, so that it does not or only to a very limited extent to caking and deposits on the burner tube. Since such caking can lead, inter alia, to malfunctions, interruptions in operation and changes in the supply of combustion air, in known burners or boilers consuming and therefore expensive additional equipment such as water-cooled grate systems or fuel pits as burners to avoid crops used. Even these additional constructive measures can be dispensed with in the "rotary kiln burner" according to the invention.

Moreover, the use of ceramic for the combustion tube has the advantage that the temperature occurring at the combustion chamber due to the combustion of the fuel is absorbed by the ceramic on the one hand, but also by the temperature of the ceramic to the air inside the combustion tube, on the other hand the fuel is discharged so that a high and relatively uniform temperature is reached within the combustion tube, which leads to a good gasification of the fuel.

According to a first preferred embodiment of the burner according to the invention, the ceramic combustion tube is surrounded by a steel shell, wherein the combustion tube and the steel shell are rotatably connected to each other, so that rotates with the combustion tube and the steel shell about its longitudinal axis. The steel jacket serves in particular to increase the stability of the ceramic combustion tube. Advantageously, moreover, the ceramic combustion tube or the steel jacket is surrounded by a double-walled cylinder which is flowed through by a liquid, for example water, so that the temperature emitted by the burner as a whole to the surroundings is limited by the double-walled cylinder. The combustion tube or the combustion tube and the steel jacket are rotatably arranged relative to the cylinder, so that the double-walled, flowed through by the liquid cylinder is formed stationary.

Advantageously, the drive device for rotating the combustion tube in addition to a motor, a drive shaft and a - non-driven - support axis. To transmit the rotational movement of the drive shaft to the combustion tube or the steel jacket surrounding the combustion tube, the drive shaft has at least two drive wheels and the support axis arranged parallel thereto at least two support wheels. Preferably, at least two races are also attached to the combustion tube or on the steel shell. For axial guidance of the races and thus the combustion tube or the steel shell, the drive wheels and preferably also the support wheels each have a U-shaped rim whose dimensions on the width of the Race rings is tuned. Instead of the formation of the rims on the drive wheels and the support wheels, it is in principle also possible that the races have corresponding grooves in which the drive wheels and the support wheels are guided. The motor for rotation of the drive shaft and thus also for rotation of the combustion tube can be operated depending on the type of fuel used in continuous operation or clocked.

According to a further particularly preferred embodiment, the drive shaft and the support shaft are arranged and designed such that the free end of the drive shaft and the corresponding end of the support shaft is selectively raised or lowered, so that the open side of the combustion tube relative to the opposite side, at the Fuel passes through the feeder in the combustion tube, can be raised or lowered. The combustion tube can thereby - seen in the conveying direction of the fuel - be placed in a rising or falling position. This can be changed within the combustion tube with otherwise unchanged speed of the drive shaft, the residence time of the fuel; an increase in the combustion tube leads to a longer residence time, a lowering to a shorter residence time of the fuel within the combustion tube.

By raising or lowering the open end of the combustion tube described above, the burner can be optimized for different fuels. In the case of fuels with an increased humidity, the residence time of the fuel within the combustion tube can thereby be increased, so that the moisture can escape better before the actual gasification or combustion of the fuel. For fuels with a lower softening point of the ash, however, can be increased by lowering the open side of the combustion tube, the feed of the fuel and thus its residence time can be reduced within the combustion chamber, so that it does not lead to slagging or sticking of the fuel within the combustion chamber comes. Depending on the angle of inclination and speed of the combustion tube can thus be determined exactly when the degassed carbon is conveyed out of the combustion tube. Initially, it has been stated that the combustion tube is arranged substantially horizontally in the ground state. Here, by "ground state" is meant the state in which the open side of the combustion tube is not - as described above - raised or lowered relative to the opposite side.

According to a further advantageous embodiment of the invention, the primary air supply means arranged within the ceramic combustion tube hollow body with a plurality of primary air nozzles, can be blown through the air in the direction of the combustion point in the combustion zone. Combustion of biomass involves a variety of physical and chemical processes, from drying to partial gasification gasification to the subsequent oxidation of combustible gases and solid carbon. In order not only to keep the degassing process going, but also to control its performance as far as possible, it is generally known to supply atmospheric oxygen to the focal point as so-called "primary air". Characterized in that the primary air supply means comprises a hollow body arranged within the ceramic combustion tube, the externally supplied combustion air is heated on its way from a fan to the primary air nozzles through the heat existing in the combustion tube, which is both positive when igniting the fuel as well as in the gasification.

In addition, the possibility is created by the formation of a large-area hollow body to provide a plurality of primary air nozzles. According to one embodiment, the hollow body is arranged on the end face opposite the open side of the combustion tube inside the combustion tube, ie. H. on the side on which the feed device protrudes into the combustion tube. The hollow body is preferably designed and arranged such that the feed device is guided through the hollow body into the interior of the combustion tube.

Preferably, the primary air nozzles are arranged and aligned so that the primary air is injected at different angles in the direction of the focal point in the combustion zone. This ensures a uniform and large-scale supply of combustion air to the burner. guaranteed. Since the fuel moves out of the lower vertex of the combustion tube due to the rotation of the combustion tube, the primary air nozzles are preferably also aligned in dependence on the direction of rotation of the combustion tube so that the stirred or circulated fuel is supplied with primary air as uniformly as possible. For this purpose, according to a further embodiment, it is provided that the primary air nozzles are aligned such that air can be blown through them at an angle greater than 45 ° to the horizontal in the direction of the fuel located in the combustion point.

In order to achieve the most complete possible oxidation of the released gaseous constituents and thus to optimize the combustion, a secondary air supply device is additionally provided, which has a secondary air supply pipe and at least one secondary air nozzle projecting into the interior of the ceramic combustion pipe, through the "secondary air". is blown into the flame of the burning fuel. The secondary air supply pipe is preferably guided by the hollow body of the primary Luftzufuhrein- direction, so that the secondary air nozzles protrude on the side opposite the open side in the combustion tube.

In addition, according to a further embodiment, it is provided that the secondary air supply device has a second secondary air supply pipe that is guided past the ceramic combustion tube or double-walled cylinder such that the end of the second secondary air supply tube protrudes from the open side the combustion tube protrudes. This ensures that there is sufficient atmospheric oxygen within the combustion tube over the entire length of the combustion tube, whereby the gasification of the volatile constituents of the fuel can be improved. In another embodiment of the burner according to the invention, the hollow body of the primary air supply means is not arranged on the end face of the combustion tube, but it extends in the longitudinal direction of the combustion tube. Preferably, the hollow body extends substantially over the entire length of the combustion tube, so that it is possible to dispense with the arrangement of a secondary air supply device in the combustion tube, since it can already be ensured by the primary air nozzles the entire length of the combustion tube is sufficient atmospheric oxygen within the combustion tube.

The hollow body is arranged stationarily above the central axis of the combustion tube, so that the combustion tube is rotatable relative to the hollow body. As a result of the rotation of the combustion tube, the fuel migrates upwards on the inner wall of the combustion tube in the direction of rotation from the lower vertex of the combustion tube until the fuel falls down again by gravity. The fuel thus performs a wave-like movement in the direction of rotation of the combustion tube and at the same time a movement in the direction of the open end of the combustion tube. The arrangement of the hollow body above the central axis of the combustion tube ensures that the hollow body and in particular its air nozzles do not come into contact with the fuel circulated by the rotation of the combustion tube, so that the air nozzles do not clog up.

According to a preferred variant of this embodiment, the hollow body and the primary air nozzles are arranged eccentrically in the combustion tube and aligned so that at least half of the fuel circulated by the rotation of the Brennroh- and moved out of the lower vertex of the combustion tube fuel is supplied with air. The air nozzles in the hollow body are preferably arranged so that the air is blown substantially perpendicular to the fuel located in the focal point. Here, the arrangement of the hollow body in the combustion tube is thus dependent on the direction of rotation of the combustion tube; the hollow body is always arranged counter to the direction of rotation offset from the center in the combustion tube. Due to the arrangement of the primary air nozzles off-center in the combustion tube is formed in the combustion tube, a rotational movement of the fuel gases, which leads to an advantageous combustion of the fuel gases.

In principle, although there is the possibility that the primary Luftzufuhrein- direction and the secondary air supply means are connected to a common fan, but it is preferably provided that the primary air supply means and the secondary air supply means are each connected to a separate blower. There is a possibility that the amount and / or pressure of the air passing through the primary air nozzles on the fuel in the combustion chamber or by the secondary air nozzles and the second secondary air supply pipe is blown into the flame, can be set independently. It is particularly advantageous if a measuring sensor is provided which measures at least one exhaust gas value of the burner, in particular the residual oxygen content, in which case the amount and / or the pressure of the air through the primary air supply device and / or through the Secondary air supply device can be set or regulated.

The heating system according to the invention consists of the burner according to the invention and at least one boiler, wherein the boiler adjacent to the open side of the burner or the combustion tube. With regard to the advantages of such a heating system, reference is first made to the previously described advantages of the burner according to the invention. The heating system is also characterized by the fact that it is modular. Depending on the desired application, in particular depending on the achievable with the heating system power and the fuel used, the burner according to the invention can be combined with different boilers.

In a preferred embodiment of the heating system, the boiler on a boiler base and a boiler shell, wherein in the boiler base a Ausbrand- or Ausglühraum is arranged as a second combustion stage and the open side of the combustion tube protrudes into the boiler base, so that the transported out of the combustion tube fixed Carbon passes into the Ausbrand- or Ausglühraum and there burns out or anneals. The boiler shell has at least one boiler wall, a Kesselde- disgust and a disposed within the boiler wall flame tube, wherein the resulting in Ausbrand- or Ausglühraum flue gases burn out together with the ascending from the combustion tube flue gases in the flame tube. In such an embodiment of the boiler, the heating system thus has, in addition to the first combustion stage realized in the burner, a second combustion stage formed in the boiler lower part of the boiler, in which only partially burned out in the first combustion stage Fuels, which still have a carbon content and thus also an energy value, can continue to burn out.

In the heating system, the biomass to be burned is divided into volatile components on the one hand and solid carbon on the other hand, the solid carbon burns not in the combustion tube but in Ausbrand- or Ausglühraum the boiler. Such a configuration is particularly advantageous when a fuel is used as the biomass, which has a relatively low ash softening point, as is usually the case with grain and straw. Characterized in that the solid carbon burns not in the very hot combustion tube, but in the lower temperature having Ausbrand- and Ausglühraum on, a slagging of the solid carbon is prevented. In particular, in the embodiment of the burner in which the hollow body of the primary air supply device extends in the longitudinal direction of the combustion tube, a secondary air supply device is provided in the boiler according to a preferred embodiment of the heating system. The secondary air supply device has a secondary air supply pipe and a hollow body arranged in the transition region between the lower boiler part and the upper boiler part. In this case, the hollow body is arranged directly adjacent or at some distance below the flame tube, so that secondary air can be blown into the flue gases rising from the combustion tube and from the combustion or annealing space, which burn out together in the flame tube. This allows the flue gases burn out optimally in the flame tube.

Preferably, the hollow body of the secondary air supply device is designed as a pipe ring with multiple air nozzles is blown through the air into the flue gases. As a result, a very good and uniform mixing of the flue gases with the secondary air can be achieved. According to a further advantageous embodiment, the air nozzles are aligned tangentially, whereby the gas mixture is placed in a rotating movement, resulting in an advantageous extension of the combustion path in the flame tube. According to another preferred embodiment of the boiler is surrounded by a preferably mehrzügigen heat exchanger, which then represents the actual outer wall of the boiler or the boiler shell of the boiler. The heat exchanger is preferably coated with Teflon or another heat-resistant material. Preferably, the boiler and / or the heat exchanger at least one train, in which the flue gases flow downwards, so that it can lead to a calming of the flue gases and in particular of dust particles contained in the flue gases. Outside the flame tube then at least one separation space is provided, in which the dust particles can fall.

According to a further embodiment, the heating system additionally has a second boiler lower part, which adjoins the boiler lower part of the boiler. The solid carbon is thereby transported through the burn-out or annealing space of the first boiler lower part into a second burn-out or annealing space formed in the second boiler lower part, so that the solid carbon can continue to burn out or anneal there. The second Ausbrand- or Ausglühraum in the second boiler base is arranged and designed so that the flue gases formed there burn out, together with the rising from the combustion tube flue gases and the flue gases from the first Ausbrand- or Ausglühraum in the flame tube.

If the heating system according to the invention has a second boiler lower part, a separate heat exchanger can advantageously be provided which is arranged on the second boiler lower part and connected to the boiler upper part of the boiler in such a way that the flue gases burning out in the flame tube are led through the trains of the heat exchanger. By using a separate heat exchanger, the achievable with the heating system according to the invention performance can be further increased. Due to the modular design of the heating system, it is possible to connect different heat exchangers with the second lower part of the boiler for different capacities.

In particular, there are a variety of ways to design and further develop the inventive burner or the heating system according to the invention. Reference is made to both the claims. 1 and 14 subordinate claims, as well as to the description of preferred exemplary embodiments in conjunction with the drawing. In the drawing, Fig. 1 shows a schematic sectional view of the invention

burner,

2 is a sketch of the internal structure of the burner according to the invention, in sectional view,

3 shows a sketch of the construction of the burner according to FIG. 2, with drive shaft and secondary air supply device, FIG.

Fig. 4 is a sketch of the drive device of the invention

burner,

5 shows a sketch of the structure of the burner in cross section, with an alternative embodiment of the primary air supply device, FIG. 6 is a schematic representation of a heating system with burner, boiler and separate heat exchanger, in longitudinal section,

Fig. 7 is a perspective view of the heating system of FIG. 6, and

Fig. 8 is a schematic representation of a variant of the heating system with burner, boiler and separate heat exchanger, in longitudinal section. 1 shows a schematic representation of a burner 1 according to the invention for the combustion of solid fuel 2, in particular of pelleted and cultured biomass, for example wood, grain or cereal-like substances such as straw or oilseed rape. The burner 1 initially has a combustion tube 3, which consists of ceramic and is arranged horizontally in the basic state shown in Fig. 1. The inner wall of the combustion tube 3 forms the focal point for the with a feeder 4 inside For conveying the fuel 2 from a - not shown here - reservoir, the feeder 4 a screw conveyor 5 on. In order to keep the process of final degassing of the fuel 2 ignited by means of an ignition device, not shown here, and to control its performance, a primary air supply device 6 is provided whose structure for a first exemplary embodiment is described below in connection with FIGS 3 and for a second embodiment in conjunction with FIG. 5 will be described in more detail.

As can be seen from FIG. 1, the feed device 4 protrudes into the combustion tube 3 on the side 8 opposite the open side 7 of the combustion tube 3 or the burner 1. The fuel 2 is thus promoted by the screw conveyor 5 in the - shown on the left in Fig. 1 - page 8 of the combustion tube. Since the burner 1 has a drive device 9, shown separately in FIG. 4, for rotating the combustion tube 3 about its longitudinal axis, the fuel 2 transported by the screw conveyor 5 into the rotating combustion tube 3 is both circulated by the rotation of the combustion tube 3 also in the direction of - shown in Fig. 1 right - open side 7 of the combustion tube moves. Both the gasification promoting circulation of the fuel 2, as well as the transport of the burning fuel 2 in the direction of the open side 7 of the combustion tube 3 and out of the combustion tube 3 out, takes place solely by the rotation of the combustion tube 3. On the arrangement of mechanical components for circulation and promotion of the fuel 2 within the combustion tube 3 can thus be dispensed with.

In particular, from FIGS. 2 and 3 it can be seen that the ceramic combustion tube 3 is surrounded by a steel jacket 10, which is non-rotatably connected to the combustion tube 3. The assembly of combustion tube 3 and steel shell 10 is also - at a radial distance - surrounded by a double-walled cylinder 11, which is traversed by a liquid, whereby the heat radiation of the burner 1 is reduced to the environment. The drive device 9 shown separately in FIG. 4 has, in addition to a motor 12, a drive shaft 13 and a support shaft arranged parallel thereto 14 on. To transmit the rotation of the drive shaft 13 to the combustion tube 3 and the combustion tube 3 tightly surrounding steel shell 10 two races 15 are arranged on the steel shell 10, on the two connected to the drive shaft 13 drive wheels 16 and the two support wheels 17 of the support shaft fourteenth rest. For axial guidance of the races 15 and thus also the steel shell 10 and the combustion tube 3, the drive wheels 16 and the support wheels 17 each have U-shaped rims 18, in which the races 15 are guided. In Fig. 1 by two bars which form an angle α to each other, indicated that the drive shaft 13 and the support shaft 14 can be deflected about its horizontal ground state so that the free end of the drive shaft 13 and the corresponding end of the support shaft 14 optional can be raised or lowered. As a result, the open side 7 of the combustion tube 3 can also be raised or lowered relative to the opposite side 8 at which the fuel 2 reaches the combustion tube 3 via the feed device 4, which is indicated by the arrow A in FIG , As a result, the combustion tube 3 can be brought into an ascending or descending position, viewed in the conveying direction of the fuel 2, as a result of which the residence time of the fuel 2 within the combustion tube 3 can be changed. When the combustion tube 3 rises, the residence time is increased, while the residence time of the fuel 2 within the combustion tube 3 is shortened when the combustion tube 3 is lowered. Both the drive shaft 13 and the support shaft 14 is mounted on the double-walled cylinder 11 via bearings 19, so that the bearings 19 are advantageously cooled by the double-walled cylinder 11 through which water flows. So that the arranged inside the cylinder 11 races

15 with the drive wheels 16 and the support wheels 17 NEN, four openings 20 are provided on the underside of the cylinder 11 through which the drive wheels 16 and the support wheels 17 project into the interior of the cylinder 11.

As can be seen from FIGS. 2 and 3, the primary air supply device 6 has one inside the ceramic combustion tube 3, at the second one

8 arranged hollow body on which a plurality of preferential is arranged movable primary air nozzles 22 through which - shown in Figure 1 as arrows 23 - primary air can be injected at different angles to the burning fuel 2 and thus into the combustion zone. The primary air supply device 6 also has a fan 24, which is connected to a second hollow body 25 arranged outside the combustion tube 3 and which is connected to the first hollow body 21 via a channel 26. In the second hollow body 25, to which the blower 24 is connected, an air pressure can be built up, so that the primary air 23 can be blown under a predetermined pressure through the primary air nozzles 22 into the combustion zone.

In the exemplary embodiment according to FIG. 5, the primary air supply device 6 likewise has a hollow body 21 arranged inside the ceramic combustion tube 3 with a plurality of primary air nozzles 22, through which primary air is blown onto the burning fuel 2. In this variant, the hollow body 21 is not arranged on the closed end 8 of the combustion tube 3, but it extends in the longitudinal direction of the combustion tube 3, preferably over the entire length of the combustion tube 3. The hollow body 21 is above and off center of the central axis of the combustion tube. 3 is arranged, so that the hollow body 21 and in particular the primary air nozzles 22 do not come into contact with the circulated by the rotation of the combustion tube 3 fuel 2.

By the rotation of the combustion tube 3, the fuel 2 migrates on the inner wall of the combustion tube 3 in the direction of rotation indicated by an arrow D from the lower vertex of the combustion tube 3 until the fuel 2 falls down again due to gravity. The fuel 2 thus undergoes a wave-like movement in the direction of rotation D of the combustion tube 2. As a result, the fuel 2 is thoroughly mixed and fresh fuel 2 is always carried upward in the direction of the combustion air introduced through the primary air nozzles 22. By the rotation of the combustion tube 2, the fuel 2 undergoes simultaneously a movement in the direction of the open end 7 of the combustion tube 2. The arrangement of the hollow body 21 above the central axis of the combustion tube 3 ensures that the hollow body 21 and in particular des- sen primary air nozzles 22 with the circulated by the rotation of the combustion tube 3 fuel 2 does not come into contact, so that it does not lead to a blockage of the primary air nozzles 22. In addition, it is ensured by the eccentric arrangement of the primary air nozzles 22 in the combustion tube 3 that at least half of the circulated and moved out of the lower vertex of the combustion tube 3 fuel 2 is supplied with primary air. As can be seen from FIG. 5, the primary air nozzles 22 in the hollow body 21 are arranged in such a way that the air is blown substantially perpendicular to the fuel 2 located in the combustion point. The arrangement of the hollow body 21 in the combustion tube 3 must therefore be selected as a function of the direction of rotation D of the combustion tube 3. Since in the embodiment according to FIG. 5, the combustion tube 3 rotates counterclockwise, the hollow body 21 is arranged offset in the clockwise direction to the center in the combustion tube 3. Due to the arrangement of the primary air nozzles 22 off-center in the combustion tube 3, a rotational movement of the fuel gases, which leads to an advantageous combustion of the fuel gases.

In the burner 1 shown in FIGS. 1 to 3, a secondary air supply device 27 is provided in addition to the primary air supply device 6, the first a secondary air supply pipe 28, a plurality of secondary air nozzles 29, a blower 30th and having a hollow body 31 as a secondary air distributor. As is apparent from FIGS. 2 and 3, the secondary air supply pipe 28 is guided both by the inner hollow body 21 and by the outer, second hollow body 25 of the primary air supply means 6. In the embodiment of the burner 1 shown in Figs. 1 to 3, the secondary air supply device 27 also has a second secondary air supply pipe 32, which is outside the double-walled cylinder 11 and thus also passed outside the combustion tube 3, wherein the end 33 of the second secondary air supply pipe 32 is bent so that it protrudes from the open side 7 into the combustion tube 3. As a result, secondary air likewise represented by arrows 34 in FIG. 1 can also be blown from the open side 7 into the flames of the combustible fuel 2. As can be seen from FIGS. 1 to 3, the burner 1 is open on one side, on this side the combustion tube 3 with its open side 7 something out protrudes the double-walled cylinder 11. The combustion tube 3 itself is of tubular design, but the combustion tube 3 is closed on the side 8 opposite the open side 7 by a base 35 connected to the steel jacket 10 in which a circular opening 36 is formed. Like the steel shell 10, the cylinder 11 also has a bottom 37 with a circular opening 38. Through the openings 36, 38 in the bottom 35 of the steel shell 10 and in the bottom 37 of the cylinder 11, the channel 26 of the primary air supply means 6 is guided, wherein on the inside of the bottom 35 of the hollow body 21 and on the outside of the bottom 37 of the two te hollow body 25 of the primary air supply means 6 is adjacent, so that the side 8 of the combustion tube 3 through the bottoms 35, 37 and in the openings 36, 37 of the bottoms 35, 37 used primary air supply means 6, in particular the two hollow body 21, 25 is closed. The end of the feed device 4 is guided within the primary air feed device 6 through the openings 36, 38, so that no further opening for the feed device 4 is required in the bottom 35 of the steel shell 10 or in the bottom 37 of the cylinder 11.

FIGS. 6 to 8 show a heating system 39 according to the invention, in which a heating boiler 40 adjoins the open side 7 of the combustion tube 3 or of the burner 1. The boiler 40 consists of a burn-out or Ausglühraum 41 as a second combustion stage having boiler base 42 and a boiler wall 43, a boiler lid 44 and a flame tube 45 having boiler shell 46th

As can be seen from FIGS. 6 and 8, the open side 7 of the combustion tube 3 protrudes into the boiler lower part 42, so that the solid carbon 47 transported out of the combustion tube 3 due to its rotation passes into the burn-out or annealing space 41 and there continue to burn out or anneal. The resulting in Ausbrand- or Ausglühraum 41 flue gases pass from the boiler base 42 in the flame tube 45 in the boiler shell 46, where they burn out together with the ascending from the combustion tube 3 flue gases. In the heating system 39 shown in FIGS. 6 and 7, the boiler wall 43 and the boiler cover 44 is surrounded by a heat exchanger 48, the the actual outer wall of the boiler 40 forms. The heat exchanger 48 has a plurality of trains 49a, 49b, wherein the flue gas flows at least in a train 49a down, so that dust particles that ascend when burning in the flame tube 45, calm down the subsequent downward flow in the train 49a and in the outside of the flame tube 45th trained deposition chambers 50 can drop.

The heating system 39 shown in FIGS. 6 to 8, in addition to the first boiler lower part 42 belonging to the heating boiler 40, also has a second boiler lower part 51 in which a burn-out or annealing space 52 is likewise formed. In this case, the solid carbon 47 is conveyed by means of suitable transport devices, for example by means of a push grate, through the burn-out or annealing space 41 of the first boiler lower part 42 into the burn-out or annealing space 52 of the second boiler bottom part 51 transported. Since the temperature in the two burnout or Ausglühräumen 41, 52 is less than the temperature within the combustion tube 3, it comes within the Ausbrand- or Ausglühräume 41, 52 does not lead to a slagging of the solid carbon 47, even if as fuel. 2 a biomass with a lower ash softening point, for example cereals, is used.

On the second boiler base 51, an additional heat exchanger 53 is arranged so that the flue gases burning out in the flame tube 45 of the boiler 40, after having passed through the trains 49a, 49b of the first heat exchanger 48, are passed through the trains 54 of the heat exchanger 53. Since no flame tube 45 is arranged inside the heat exchanger 53, a plurality of trains 54 can be arranged in the heat exchanger 53, so that the heat exchanger 53 has a correspondingly large surface area, whereby a heating system 39 with a high power of several 100 kW is achieved can be.

Exhaust values of the boiler 40 or of the heating system 39, in particular the residual oxygen content of the flue gases, can be measured via a measuring sensor 55 which is arranged in the exhaust duct 56 of the heating system 39. Depending on the measured exhaust gas value then the amount and / or pressure of the air through the primary air supply means 6, ie the primary air 23 or the air through the secondary Luftzufiihreinrichtung 27, ie the secondary air 34, are set or regulated.

The illustrated heating system 39 finally also has a housing 57 surrounding the drive device 9, through which the second secondary air supply pipe 32 is also guided. Through the housing 57 is in addition to a mechanical protection of the drive device 9 and an improved

Tightness of the burner 1 is reached, so that it is ensured that during operation within the heating system 39 always a negative pressure is present, so that no flue gas can escape to the outside.

On the side of the heating system 39 opposite the burner 1, a dust and ash box 58 is arranged, in which the mineral ash 59 accumulating at the end of the second burn-out or annealing space 52 and the precipitation spaces 50 are collected.

In the embodiment variant of the heating system 39 according to FIG. 8, in which the hollow body 21 of the primary air supply device 6 extends in the longitudinal direction of the combustion tube 3, the secondary air supply device 27 is not provided in the burner 1 but in the heating boiler 40. The secondary air supply device 27 has a secondary Luftzuftihrrohr 28 and arranged in the transition region between the lower boiler part 42 and the boiler shell 46 hollow body 31. The hollow body 31 is arranged here with some distance below the flame tube 45, so that secondary air 34 can be blown into the rising from the combustion tube 3 and from the Ausbrand- or Ausglühraum 41 flue gases that burn together in the flame tube 45. By a targeted adjustment of the amount of secondary air 34, the flue gases can optimally burn out in the flame tube 45. The hollow body 31 may alternatively also immediately adjacent, d. H. be arranged without a gap to the underside of the flame tube 45.

As is apparent from Fig. 8, the hollow body 31 of the secondary air supply means 27 is formed as a pipe ring with a plurality of air nozzles is blown through the secondary air 34 into the flue gases. The air nozzles are aligned tangentially, whereby the gas mixture is placed in a rotating movement, resulting in an advantageous extension of the combustion tion path in the flame tube 45 leads. In addition, a very good and uniform mixing of the flue gases with the secondary air 34 is achieved. In the combustion tube 3 here is a Abstreifblech 60 is arranged, which ensures that by the screw conveyor 5 tracked fuel 2 is moved forward, in the direction of the open end 7. In addition, in the embodiment shown in FIG. 1, the heating system 39 also has a tertiary air supply device with a third blower 61 and a tertiary air supply pipe 62, in which a plurality of air nozzles is formed. By means of the tertiary air supply device, afterburning air is introduced into the two burnout zones. Ausglühräume 41 and 52 blown, whereby the burnout of the carbon 47 is further improved. The remaining mineral ash 59 is then transported into the dust and ash box 58 by means of the transport devices 63, which has a plurality of transporting blades 64. The transporting vanes 64 are fastened to the conveyor belt in such a way that they move in the forward movement of the transport devices 63 -shown in FIG. 8 with a dashed line and the reference numeral 64 '- the carbon 47 in the direction of the burner 1 and in the reverse movement the carbon 47 in the direction of the dust and ash box 58 promote.

From the above description of the preferred embodiments of the burner 1 according to the invention and of the heating system 39, it can be seen that the heating system 39 has a total modular construction, so that it depends on the desired performance and on the type of fuel 2 used next to the burner 1 may have different components. In principle, it is also possible for the burner 1 to be connected only to a conventional heating boiler having a heat exchanger if, for example, wood is used as the fuel 2 whose ash softening point is so high that the wood is completely inside the combustion pipe 3 burned and thus can be dispensed with the use of a second combustion stage.

Claims

claims:

A burner for the combustion of solid fuel (2), in particular biomass, with a combustion tube (3), with a burner, with a feed device (4) for conveying the fuel (2) to the burner (4) and with a Primary air supply device (6),

characterized,

that the combustion tube (3) is arranged substantially horizontally in the ground state and consists of ceramic,

in that the feed device (4) projects into the combustion tube (3) on the side (8) opposite the open side (7) of the combustion tube (3), and in that a drive device (9) rotates the combustion tube (3) about its longitudinal axis is provided,

such that the combustion tube (3) is rotatable in such a way that the fuel (2) conveyed from the supply device (4) to the combustion station is both circulated by the rotation of the combustion tube (3) and in the direction of the open side (7) of the combustion tube (3) is moved.

2. Burner according to claim 1, characterized in that the ceramic combustion tube (3) by a steel shell (10) is surrounded, wherein the steel shell (10) rotatably connected to the combustion tube (3) is connected.

3. Burner according to claim 1 or 2, characterized in that the ceramic combustion tube (3) or the steel shell (10) by a double-walled, liquid-flow cylinder (11) is surrounded, wherein the combustion tube (3) or the Steel shell (10) relative to the cylinder (11) is rotatable.

4. Burner according to one of claims 1 to 3, characterized in that the drive device (9) has a motor (12), a drive shaft (13) and a support shaft (14).

5. Burner according to claim 4, characterized in that on the combustion tube (3) or on the steel shell (10) at least two races (15) ange- are arranged, and that the drive shaft (13) at least two drive wheels (16) and the support shaft (14) at least two support wheels (17), wherein the drive wheels (16) and the support wheels (17) preferably each have a U-shaped rim ( 18) for axial guidance of the races (15).

6. Burner according to claim 4 or 5, characterized in that one end of the drive shaft (13) and the support shaft (14) can be raised or lowered, so that the open side (7) of the combustion tube (3) relative to the opposite side (8 ) is raised or lowered.

7. Burner according to one of claims 1 to 6, characterized in that the primary air supply means (6) within the ceramic combustion tube (3) arranged hollow body (21) with a plurality of primary air nozzles (22) through the air in the direction the burner can be blown into the combustion zone.

8. Burner according to claim 7, characterized in that the hollow body (21) extends in the longitudinal direction of the combustion tube (3), preferably substantially over the entire length of the combustion tube (3), wherein the hollow body (21) fixed above the Center axis of the combustion tube (3) is arranged so that the combustion tube (3) relative to the hollow body (21) is rotatable and the hollow body (21) with the by the rotation of the combustion tube (3) circulated fuel (2) does not come into contact.

9. Burner according to claim 8, characterized in that the hollow body (21) and the primary air nozzles (22) are arranged eccentrically in the combustion tube (3) and aligned such that at least half of the by the rotation of the combustion tube (3) circulated and is supplied with air from the lower apex of the combustion tube (3) moved out fuel (2), wherein the air is blown substantially perpendicular to the fuel located in the combustion point (2).

10. Burner according to one of claims 1 to 9, characterized in that a secondary air supply means (27) is provided which has a secondary air supply pipe (28) and at least one into the interior of the ceramic combustion tube (3) projecting secondary air nozzle (29 ), through the air in the Flame of the combustible fuel (2) can be blown, which is located in the focal point, wherein the secondary air supply pipe (28) is preferably guided by the hollow body (21) of the primary air supply means (6).

11. Burner according to claim 10, characterized in that the secondary air supply means (27) has a second secondary air supply pipe (32), which is externally past the ceramic combustion tube (3) and whose end (33) from the open side (7 ) projects into the combustion tube (3), so that air can be blown into the flame of the burning fuel (2), which is located in the focal point.

12. Burner according to claim 10 or 1 1, characterized in that the primary air supply means (6) and the secondary air supply means (27) are each connected to a separate blower (24, 30), and that the amount and / or the Pressure of the air which is blown through the primary air supply device (6) and / or the secondary air supply device (27) into the combustion chamber or into the flame of the combustible fuel (2) is adjustable,

13. Burner according to claim 12, characterized in that a sensor is provided which measures at least one exhaust gas value of the burner (1), so that the amount and / or the pressure of the air through the primary air supply means (6) and / or the Secondary air supply means (27) is adjustable or controllable in dependence on the measured exhaust gas value.

14. Heating system with a burner (1) according to one of claims 1 to 13, for the combustion of solid fuel (2), in particular biomass, and with one on the open side (7) of the combustion tube (3) of the burner (1). adjacent boiler (40).

15. Heating system according to claim 14, characterized in that the boiler (40) consists of a combustion chamber (41) as a second combustion stage having boiler lower part (42) and a Kes beveling wall (43), a boiler cover (44). and a boiler shell (46) having a flame tube (45), wherein the open side (7) of the combustion tube (3) protrudes into the boiler base (42), so that the out of the combustion tube (3) transported out solid carbon (47) in the Ausbrand- or Ausglühraum

(41) passes and there burns out further or anneals and wherein the combustion in the Ausbrand- or Ausglühraum (41) resulting flue gases burn out together with the from the combustion tube (3) rising flue gases in the flame tube (45).

16. A heating system according to claim 15, characterized in that a secondary air supply device (27) is provided, which a secondary air supply pipe (28) and one in the transition region between the boiler base

(42) and the boiler shell (46) arranged hollow body (31), wherein the hollow body (31) is disposed immediately adjacent or at some distance below the flame tube (45), so that air from the burner tube (3) and the From the burn-out or Ausglühraum (41) rising flue gases can be blown, burn out in the flame tube (45).

17. Heating system according to claim 16, characterized in that the hollow body (31) of the secondary air supply device (27) is designed as a pipe ring with a plurality of air nozzles is blown through the air into the flue gases, wherein the air nozzles are preferably aligned tangentially.

18. Heating system according to one of claims 15 to 17, characterized in that the boiler wall (43) by a preferably mehrzügigen heat exchanger (48) is surrounded, wherein the heat exchanger (48) is preferably coated with Teflon or other heat-resistant material.

19. Heating system according to one of claims 15 to 18, characterized in that the heating boiler (1) and / or the heat exchanger (48) at least one train (49 a), in which the noise gases flow downwards, and that outside of the flame tube (45 ) at least one separation chamber (50) is provided, can sink into the dust particles.

20. Heating system according to one of claims 15 to 19, characterized in that adjacent to the boiler lower part (42) of the boiler (40), a second boiler lower part (51), and that the solid carbon (47) through the Ausbrand- or Ausglühraum ( 41) of the first boiler lower part (42) into one in the second boiler lower part (51) formed second Ausbrand- or Ausglühraum (52) is transported and further burns out or anneals there, whereby also in the second Ausbrand- or Ausglühraum (52) resulting flue gases together with the from the combustion tube (3) Burn out rising flue gases in the flame tube (45).

21. Heating system according to one of claims 15 to 20, characterized in that a heat exchanger (53) is provided, which is so connected to the boiler shell (46) of the boiler (40), that in the flame tube (45) ausbrennenden noise gases are passed through the trains (54) of the heat exchanger (53), wherein the heat exchanger (53) is preferably arranged on the second boiler lower part (51).

22. Heating system according to one of claims 14 to 21, characterized in that a measuring sensor (55) is provided, the at least one exhaust gas value of the boiler (40), in particular the residual oxygen content of the flue gases in the exhaust passage (56) of the boiler (40). measures, and that in dependence on the measured exhaust gas value, the amount and / or pressure of the air through the primary air supply means (6) and / or the secondary air supply means (27) is adjustable or adjustable.